This invention relates to composite panel or shape forming apparatus and more particularly, it concerns an improved apparatus for continuously forming flat sheets or shapes from a composite of reinforcing fibers and particulate filler in a matrix of thermosetting resinous material by the applying of the materials of the composite between a pair of continuous sheet-like carriers and pulling the sheets and material through a linear series of successive compacting, treating shaping and curing stations in a manner such that the flat sheet or shape being so continuously formed may be finished and severed into panels ready for use.
Various forms of apparatus are known in the prior art by which the individual components of a fiber reinforced board or sheet to be formed are distributed either simultaneously or successively onto a continuously moving surface, such as an endless conveyor or elongated carrier sheet, and then passed through successive treatment stations by which a continuous form of the board or sheet being manufacturing emerges for cut-off and stock piling. See, for example, U.S. Pat. Nos. 3,071,180 and 3,109,763 issued to Joseph S. Finger et al. While prior forms of such apparatus are admirably suited to high speed production of structural panels and the like, specific apparatus heretofore available have been generally deficient from the standpoint of adaptability to different constituent materials to be employed in the composite board, diverse cross-sectional shapes in the board, sheet or panel being formed as well as capability for providing a truly uniform distribution of composite material components throughout the resulting panel or board product. For example, relatively high percentages of inexpensive particularized inorganic fillers have been found desirable in structural panels both from the standpoint of reduced costs and enhanced nonflammability. Such materials, however, have been difficult to handle in prior apparatus because of the extent to which they increase viscosity of their mixture in resins. Also, composite boards are conventionally formed in a corrugated cross-section for use in various structural applications where longitudinal rigidity as a result of the corrugated cross-sectional configuration is needed. Quite often, however, it is either necessary or desirable to change the specific cross-sectional configuration. In prior apparatus, however, this could be accomplished only by the substitution of costly dies and molds and involves a time consuming and tedious procedure.
From the standpoint of component intermixing and uniformity of distribution, such prior apparatus has been found to lack facility for varying percentages of components incorporated in a continuously formed board and also have demonstrated deficiencies in achieving a uniform distribution of the components throughout the product. In this latter respect, fibrous components employed principally as reinforcement in a matrix resin pose problems of distribution as a result of interfiber adherence due either to electrostatic traction or surface tension and further are subject to non-uniform distribution as a result of non-uniform directional forces imposed on the fibers as they are distributed onto the matrix.
In light of these exemplary deficiencies, a need for improvements in both methods and apparatus for forming such composites board is apparent.